Locomotive superheater construction



Feb. 26, 1935. McGREW LOCOMOTIVE SUPERHEATER CONSTRUCTION Filed Nov. 4, 1935 in my prior Patent No. 1,918,6 55,

Patented Feb. 26, 1935 UNITED STATES rA'TENTlo Fic Looo o'rIvE SUPERHEATER, CONSTRUCTION I John A. McGrew, Albany, N. I H Application November 4, 1933, Serial No. 696,726

4 Claims. (01, 122%481) This invention relates to superheater, units for boilers and particularly to improvements in combination superheater and fire arch constructionsforlocomotive boilers of the type disclosed. issued July.

In the patent just referred to, a superheater is disclosed which is positioned in the firebox of a locomotive boiler, this superheaterbeing so formed and so disposed in thecombustion space of the boiler that it comprises not only a means for effecting the superheating of the steam developed in the steam space of the boiler but also performs the functions of a fire arch or fire bridge, deflecting the flame and products of combustion originating in the firebox grate rearwardly and upwardly in the customary manner so that such flame and gas do not pass directly to and into the fire tubes of the boiler. The present invention contemplates an improved construction for this superheater unit whereby it is rendered more durable in use, without at the same time making it either more expensive to construct or heavier and without sacrificingany of the advantages realized by the specific formof superheater unit'first patented. I

It will be appreciated by those skilled in the art that a superheater unit positioned in thefirebox of-a locomotive is subjected to intense heat and that such a unit is also-at times subjected to very considerable vibration due to motion of the locomotive. When the superheater unit is subjected to intense heat and considerable vibrations, there is a tendencyforthe metal of which it is fabricated to yield'and for the superheater to become distorted. It is undesirable to place in the firebox bracing or sustaining rodsinasmuch as these add to the complexity of the structure and the: weight of the locomotive. -I have therefore perfected a superheater unit inwhich, by the re-design and rearrangement of its own parts or elements, a stronger and more durable unit is realized.

Thus, in my prior patent the superheater unit comprises essentially a plurality of straight parallel tube portions connected at their ends by bends, these parallel portions being positioned in an inclined plane in the inlet and outlet branches and being unsupported from their lower sides. The improved superheater unit which comprises the subject matter of the present invention contemplates that these parallel portions of the unit be horizontally disposed, although still arranged in an inclined plane, and that the inlet and outlet branches of the superheaterlie beneath the-same and in contact therewith, thus constituting supporting members for the main portion of the superheater and eliminating any tendency of portions of the unit to sag or become distorted in use, Icontemplate 5 that the rearrangement'of the various portions of the unit'may be -:madein various ways to render the entire assembly self-supporting, and in the accompanyingdrawing I have illustrated one satisfactory construction by way of example. 10;

'In'the drawing: x 1

,''Figure' 1 is aside-view of the rear end of a locomotive boiler, partly in elevation and partly broken away to show the superheater unit and the interior construction of; the boiler;

Figure 2, isa top-plan view'of the same, partly broken away to show'details of the superheater unit and-boiler construction; 7 v

Figure Sis a section online 33-of Figure 1; and j v v Figure 4 is asection on line 4-4 of Figure 1.

' The outer shell of the boiler is'indicated at -10 and'the combustion space at 11.1 The crown sheet is indicated at112,;, tube sheet at 13, rear throat sheet at 14, and fire tubes at-15: The boiler grate 25 isnot shown and may be of anywell-known type such asnow employedinconnection with boilers of the construction illustrated. The superheater unit isgenerally indicated at S and comprises essentially an elongated tortuous steam conduit, 3 into one end-of Which-saturated steam from the boiler steam space is passed and from the other end of which superheated steam moves toward a front end throttle and engine cylinders, as fully set forth in my. prior patent previously referred 3 to. The superheater steam conduit has a plurality of portion's20, each'of which is horizontally disposed, allof these parallel portions being positioned in a plane inclined to the horizontal and which is normal to avertical plane passing through the longitudinal axis of theboiler. The ends of the horizontal portions are connected by bends21 so that steam entering the, lowermost such portion passes successively through the several portions until it reaches the uppermost por- 45 tion.

The lowermost conduit portion 20 is connected by a bend 22 to a rearwardly and upwardly extending portion 23 which turns forwardly around the uppermost conduit portion 20 and extends horizontally to a point adjacent the rear tube sheet 13 where it is connected, preferably by welding, to the rear end of a saturated steam conduit 23' which communicates with the steam space of the boiler. Portion 23 of the superheater unit is hereinafter designated the inlet branch since it is through this portion that the steam flows to the main part or mid-section of the superheater comprising conduit portions 20. The uppermost conduit portion 20 is connected by a downtake 24 to the lower end of the upwardly 23' and 27 are attached at their forward ends-to the boiler structure and hence constitutesup porting means for the superheater unit within the firebox, while at the same time permittingslight movements of this unit due to changes in=dimenson of the metallic parts of the boiler resulting from changes in temperature. The weight of the superheater unit is carried by a, cross rail 28', the ends of" which are secured to the mud ring- 29 of the boiler structure. Interposedibetween the rail 28 and the superheater: are rest plates 30 upon which the superheater directly bears and with respect to which it may have slight rolling movements due to expansion and contraction of pipes 23 relatively to the re-. mainderof the boiler structure,

Rows of firebrick are indicated at 30and extend between the side walls of the combustion space to the superheater unit, and it will be appreciated that, order: that the products oi combustion arising from the grate be deflected by the superheater unit after the manner of a firebridge, additional fire-bricks may be positioned, or refractory material oi any: typepositioned at various points as desired, toprevent directlpassage of the products of combustion into the fire tubes of the boiler. In cros's-sectionthe superheater conduit ispreferably as shown in Figure 4, websbeing provided for the purpose of rapidly transmitting the heat fromthe lower side of each tube section to the upper sideg-thus preventing burning out of the lower side. These inwardly projecting webs likewise insure that all portions heater and fire-bridge, itis rende'redmore stable against-the combined action of grate heat and vibration and without necessitating the use" of be deemed desirable to make changes in the arrangement of the various sections of the tortuous conduit so that the unit possesses greater strength for a given weight of metal, and the invention contemplates that numerous such changes may be made without departing therefrom.

Having thus described the invention, what is claimed as new anddesired to be'secured by Letters Patent-is:

1. In combination with a locomotive boiler having a firebox, of a combined superheater and fire bridge, said combined superheater and fire bridge ,comprisingasingle elongated conduit, an intermediate part of which comprises a series of straight portions arranged in substantial'parallelism and close relationship in the plane inclined to the horizontal so as to rearwardly de-' fleet flame and products of combustion, and the end parts of which are disposed substantially at right angles2to: the straight portions: of f. said'iintermediate-part and in spaced-parallel relation; ship in a plane-parallel to-the. plane 'ofthe. in termediate part, saidend parts underlying and supporting said intermediate part and being in turn supported by the boiler. V 2; In combination witha locomotive boiler having; a firebox, of a combined superheater and fire bridge, said-combined superheater andfire bridge comprising an elongated conduit for steam having a plurality of portions arrangedin substantial parallelism and" generally in a common inclined plane, and spaced additional portions disposed in a parallel plane, said last mentioned, portions being disposed transversely of said firstmentioned portions and being adapted to underlie and support said first mentioned portions, said additional portions being in turn supported by the boiler; 3. .Invcombination with alocomotive boiler having a-firebox, of a combinedsuperheater and fire bridge, said'combined superheaterand fire bridge comprising an elongated conduit for. steam having an inclined tortuous intermediate portion and inlet and outlet branchessaid inlet and outlet branches being disposed to underlie andsupport the intermediate portion andbeing in turn supported upon the boiler.

4. Incombination with a locomotive boiler having afirebox, of a'conibined superheater. and fire bridge,.,said combinedsuperheater and fire bridge comprising an elongated conduit for steam having aninclined tortuousv intermediate portion and inlet and outlet branches, said inlet and outlet branches being disposed to underlie and support the intermediate portion, the lowermost part of each branch, having a bearing surface, and a supportin'gmember extending transversely of the firebox upon which said bearing. surfaces rest, the-ends of said member being secured to the mud ring'of the boiler.

JOHN A. MCGREW. 

